Circular 8, 12 January 2001The IAU General Assembly has been held in Manchester (UK) August 7-18, 2000. The report of the Joint Committee was presented in the Joint Discussion 2, Towards models and constants for sub-microarcsecond astrometry, on August 10. The Resolutions prepared by the Working Group Relativity in Celestial Mechanics and Astrometry (RCMA) and the Joint Committee, and presented by Division 1, were adopted as Resolutions B1.3 to B1.5 and B1.9 by the General Assembly (see their text here). B1.3 Definition of Barycentric Celestial Reference System and Geocentric Celestial Reference System B1.4 Post-Newtonian Potential Coefficients B1.5 Extended relativistic framework for time transformations and realisation of coordinate times in the solar system B1.9 Re-definition of Terrestrial Time TT JCR08.2. Closure of the Joint Committee As a result of the work of our Joint Committee and of the Working Group Relativity in Celestial Mechanics and Astrometry (RCMA) of the IAU Division 1, a very fruitful collaboration, four Resolutions B1.3 to B1.5 and B1.9 were adopted by the IAU. Since the specific work concerning time and frequency applications is well covered by Resolutions B1.5 and B1.9, an important part of the original objectives of the JCR has been completed. The BIPM, therefore, has proposed to the IAU to terminate the Joint Committee and to continue to collaborate in the framework of the RCMA working group. To reflect the increasing importance of metrology, including under this term all astro-geodetic measurements applied to space-time reference systems, the BIPM proposed that the name of the RCMA be extended to RCMAM: Relativity in Celestial Mechanics, Astrometry and Metrology. Therefore I announce now the closure of this Joint Committee. I wish to thank all members particularly those whose work is reflected in the correspondence of the Joint Committee, or in the related publications. The web site will remain open for some time and I shall try to maintain the publications. The mail exploder jcr@bipm.org will be discontinued shortly. I wish all of you a happy New Year 2001 and look forward to further discussions, do not hesitate to contact me at gpetit@bipm.org. Gerard Petit |